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.Dd November 21, 2001
.Dt VFS_GETNEWFSID 9
.Os
.Sh NAME
.Nm vfs_getnewfsid
.Nd "allocate a new file system identifier"
.Sh SYNOPSIS
.In sys/param.h
.In sys/mount.h
.Ft void
.Fn vfs_getnewfsid "struct mount *mp"
.Sh DESCRIPTION
The
.Fn vfs_getnewfsid
function allocates a new file system identifier for the mount point given.
File systems typically call
.Fn vfs_getnewfsid
in their mount routine in order to acquire a unique ID within the system
which can later be used to uniquely identify the file system via calls such as
.Xr vfs_getvfs 9 .
.Pp
The actual
.Vt fsid
is made up of two 32 bit integers, that are stored in the
.Vt statfs
structure of
.Fa mp .
The first integer is unique in the set of mounted file systems,
while the second holds the file system type.
.Bd -literal
typedef	struct fsid {
	int32_t val[2];
} fsid_t;
.Ed
.Sh PSEUDOCODE
.Bd -literal
xxx_mount(struct mount *mp, char *path, caddr_t data,
	struct nameidata *ndp, struct thread *td)
{
	...
	vfs_getnewfsid(mp);
	...
}
.Ed
.Sh SEE ALSO
.Xr vfs_getvfs 9
.Sh AUTHORS
This manual page was written by
.An Chad David Aq Mt davidc@acns.ab.ca .
